package day07;

import java.util.Random;

public class VerificationCode {
    public static void main(String[] args) {
        String code = generateVeriCode(4);
        System.out.println("验证码："+code);
    }
    public static String generateVeriCode(int len){
        String code = "";
        char[] chs = {'a','b','c','d','e','f','g','h','i','j',
                'A','B','C','D','E','F','G','H','I','J',
                '0','1','2','3','4','5','6','7','8','9'
        };
        Random rand = new Random();
        for (int i = 1; i <= len; i++) {
            //int index = (int)(Math.random()* chs.length);
            int index=rand.nextInt(chs.length);//随机下标
            code+=chs[index];
        }
        return code;
    }
}
